Various types of mobile devices have been used for communication among people or for location monitoring applications. For example, a conventional cellular phone can be used for voice and data communication. A conventional global positioning system (GPS) watch can be used for navigation in the mountains. In such conventional devices, the antenna is embedded within the enclosure of the cellular phone or the GPS watch, and the ground plane of the antenna is typically shared with the ground plane of the printed circuit board of the device. One of the drawbacks of such conventional devices is that the signal quality of the antenna is limited because of the small size of the printed circuit board enclosed within the enclosure of the devices. Another drawback of the conventional devices is that the signal quality of the antenna may be adversely affected by the electrical characteristics of the printed circuit board because it shares the electrical ground with other components on the printed circuit board.
Therefore, there is a need for multiband antenna for a mobile device that can address the above issues of conventional mobile devices.